Biomedical Engineering and Bioengineering Commons^™

Water Permeation Through Single Sub-Micron Pores In Single Layer Graphene Measured By A Micro-Particle Image Velocimetry Technique, Samuel F. D. J. Gomez, Michael S. H. Boutilier

Chemical and Biochemical Engineering Publications

Graphene holds potential as a high permeance membrane material for separation applications owing to its single atom thickness. Transport rates through graphene pores ultimately determine membrane performance and are an area of focus of design efforts. In this regard, single pore flow rate measurements are desirable because they are not influenced by material defects present in large-area samples and are unaffected by modeling assumptions used in simulations. However, measuring liquid flow rates through single graphene pores is challenging. In this paper, we establish a micro-particle image velocimetry technique to measure flow rates through single pores or small permeable areas by …

Design And Testing Of A Prototype Prosthesis For Pediatric Upper-Limb Transradial Amputees To Provide Adjustable Size And Modular Characteristics, Paul Heli

Master's Theses

This study was conducted to develop a financially accessible body-powered upper-limb prosthetic socket that can be adjusted to maintain fit and function for a growing child with a transradial amputation. The main objectives of the study were to design, manufacture, and test a device that was comfortable, functional, affordable, and adjustable. The socket was designed to be comfortable using global variables controlling the computer-aided design (CAD) model size with user-specific measurements. Comfort was also incorporated using shape-forming of the socket for specific residual limb features. The device was designed to perform the two main functions of suspension, or attachment to …

Development Of A Pressure Sensing System Coupled With Deployable Machine Learning Models For Assessing Residual Limb Fit In Lower Limb Prosthetics, Maxwell D. Lewter

Master's Theses

Lower limb amputations pose significant challenges for patients, with over 150,000 cases annually in the U.S., leading to a high demand for effective prosthetics. However, only 43% of lower limb prosthetic users report satisfaction, primarily due to issues with socket fit, which is critical for comfort, stability, and preventing injury. This study presents a deployable sensing system for potentially real-time monitoring of prosthetic socket fit by using pressure sensors and convolutional neural networks (CNNs) to analyze the pressure distribution within the socket. A novel CNN architecture, utilizing both dilated and strided convolutions, is proposed to effectively capture spatial-temporal patterns in …

Multifunctional Peptides To Improve Nucleic Acid Delivery For Ovarian Cancer Treatment, Kharimat Lora Alatise

All Dissertations

RNA interference (RNAi) therapies, such as small interfering RNA (siRNA), offer a high-precision approach to reducing the expression of disease-promoting genes with minimal off-target effects. For aggressive diseases like ovarian cancer, RNAi therapy can serve as a robust treatment modality if delivered successfully. Over 70% of ovarian cancer patients are diagnosed in stages three and four, where the disease becomes more difficult to treat. High relapse rates and drug resistance in these stages demonstrate the need for novel strategies to sensitize tumors to chemotherapy, making siRNA a promising avenue for targeting resistance-associated oncogenes.

However, the delivery of siRNA remains a …

Surgical Suturing Skill Assessment Using Estimated Hand Roll Angle From A Deep-Learning Computer Vision Algorithm, Jianxin Gao, Amir Mehdi Shayan, Simar P. Singh, Joe Bible, Ravikiran Singapogu, Richard E. Groff

Publications

This paper proposes a deep-learning computer vision algorithm to estimate hand roll angles for metric-based assessment of surgical suturing skills. The number of rolls metric, previously calculated directly from IMU data, counts the number of hand roll reversals during a single suture. To calculate this metric using computer vision, we apply a deep-learning algorithm that can reliably estimate hand roll angles after training on suturing videos collected on the SutureCoach simulator. Results show that the estimation accuracy of the deep-learning algorithm is robust to different video backgrounds. The number of rolls metrics were used to analyze suturing performance in the …

The Effect Of Pressure Gradients On Perceived Discomfort, Zachary Bush

All Theses

Introduction:

A pressure gradient is where high and low pressure meet. It is responsible for displacement and irritation of the skin commonly caused by tight bandages, bracelets, or socks. The irritation is at the edge where the skin is displaced by the high and low pressure. An analysis of the effect pressure gradients have on discomfort would have significant medical relevance for any device, fixture, or clothing pressed against the skin at high pressure. This primarily includes prosthetic and orthotic devices.

The bottom surface of the heel provides a naturally circular, uniform pressure profile. This makes it the optimal testing …

Synthesis And Process Optimization Of Cellulose Nanocrystals From Miscanthus X. Giganteus For Commercial Viability, Jaspreet Kaur

Graduate Theses and Dissertations

Cellulose nanocrystals (CNCs), derivatives of an abundant biopolymer, i.e., cellulose, are emerging as promising alternatives to petrochemical-based products due to their unique properties, including biodegradability, low toxicity, high strength, low density, large surface area and low coefficient of expansion. CNCs have diverse applications ranging from food packaging and textiles to drug delivery and medical implants, etc. Despite their potential, the widespread commercialization of CNCs faces significant hurdles owing to the high environmental burden and production costs. They are mainly driven by the commonly used source utilized for CNC synthesis i.e., wood and the intensive synthesis process i.e., requirement of …

Comparing Continuum And Direct Fiber Models Of Soft Tissues: An Ocular Biomechanics Example Reveals That Continuum Models May Artificially Disrupt The Strains At Both The Tissue And Fiber Levels, Xuehuan He, Mohammad R. Islam, Fengting Ji, Bingrui Wang, Ian A. Sigal

Mechanical Engineering Faculty Publications

Collagen fibers are the main load-bearing component of soft tissues but difficult to incorporate into models. Whilst simplified homogenization models suffice for some applications, a thorough mechanistic understanding requires accurate prediction of fiber behavior, including both detailed fiber-level strains and long-distance transmission. Our goal was to compare the performance of a continuum model of the optic nerve head (ONH) built using conventional techniques with a fiber model we recently introduced which explicitly incorporates the complex 3D organization and interaction of collagen fiber bundles [1]. To ensure a fair comparison, we constructed the continuum model with identical geometrical, structural, and boundary …

Precision And Efficacy Of Rna-Guided Dna Integration In High-Expressing Muscle Loci, Made Harumi Padmaswari, Gabrielle Bulliard, Shilpi Agrawal, Mary S. Jia, Sabin Khadgi, Kevin A. Murach, Christopher E. Nelson

Biomedical Engineering Faculty Publications and Presentations

Gene replacement therapies primarily rely on adeno-associated virus (AAV) vectors for transgene expression. However, episomal expression can decline over time due to vector loss or epigenetic silencing. CRISPR-based integration methods offer promise for long-term transgene insertion. While the development of transgene integration methods has made substantial progress, identifying optimal insertion loci remains challenging. Skeletal muscle is a promising tissue for gene replacement owing to low invasiveness of intramuscular injections, relative proportion of body mass, the multinucleated nature of muscle, and the potential for reduced adverse effects. Leveraging endogenous promoters in skeletal muscle, we evaluated two highly expressing loci using homology-independent …

Alteration Of Peripheral Cytokines In Alzheimer’S Disease, Zhengshi Yang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alzheimer’s disease (AD) is a progressive neurodegenerative disease with the clinical symptoms of gradual cognitive decline and memory loss. Biologically, abnormal accumulation of Aβ (Aβ) plaque and tau tangles in the brain are the core pathological hallmarks in AD. Although inflammatory response is not specific to AD, emerging evidence suggests that the disrupted innate immune system within the central nervous system, particularly microglial activation, might act as the bridge linking Aβ aggregation to pathological phosphorylation and aggregation of tau. The inflammatory response was suggested to initially have a neuroprotective role of attempting to clear Aβ plaques, and then become neurotoxic …

Modeling Instrument Design Risks In Medical Device Reprocessing, Manuel Andres Gutierrez

All Dissertations

Medical device reprocessing is an essential practice in healthcare delivery. While FDA regulations require device manufacturers to develop and validate reprocessing procedures, the increasing complexity of medical device designs and their use environments can increase the risks of inadequate reprocessing and associated device malfunctions and potential patient injury. While some design features present known difficulties for reprocessing, critical information needed to define relative risks or feature-specific parameters that increase or decrease risks of inadequate reprocessing is lacking. There is an urgent need for tools to quantify and predict reprocessing risks associated with design features used in surgical instruments.

The broad …

Feasibility Study On Microwave Glucose Level Monitoring, Ricardo Cepeda

Theses and Dissertations

Diabetes management heavily relies on regular blood glucose monitoring, which traditionally involves invasive techniques. In recent years, significant research has been directed towards developing non-invasive glucose monitoring methods, particularly using electromagnetic waves. This study explores the feasibility of detecting blood glucose levels non-invasively by measuring the resonant frequency shifts of an antenna, influenced by the dielectric properties of blood. Microwave measurement techniques have garnered attention due to their ability to safely penetrate human tissue and detect biochemical markers like glucose. While previous studies have established a link between glucose concentration and dielectric properties, many techniques suffer from poor sensitivity or …

Assessing Reproducibility Challenges In Clinical Metabolics, Darcy Lin Cochran

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Current metabolomics research is expanding to be multiplatform and interdisciplinary. Metabolomic analysis has the potential to provide detailed insight into any biological system of interest to analyze the underlying molecular mechanisms of variables like environment, disease, and genetics. Human clinical metabolomics is a major research area that is often focused on finding biomarkers or panels of biomarkers for different diseases. However, results are difficult to compare across different laboratories since the field of metabolomics has yet to widely adopt best practices for sample preparation, data acquisition and data processing, results are difficult to compare across different laboratories.

This thesis focuses …

Study Of Temperature Effects Of Glucose And Microwave Dielectric Dispersion Model, Ethan Grant Boone

Theses and Dissertations

In this study, the temperature effect of dielectric properties in various aqueous solutions containing glucose are examined. A design for a new testing chamber is introduced to provide improved conditions for testing to ensure accurate and precise measurements. A N-SMA Adaptor is used when obtaining dielectric characteristics of glucose solutions ranging 100-300mg/dl. Dielectric parameters are obtained adopting a modified Debye dispersion model. MATLAB is used to confirm coaxial dimensions are suitable fabrication designs using fixed dielectric parameters of air and water. Simulations and design models were implemented utilizing ANSYS High Frequency Structure Simulator and 3-D Modeler software to develop the …

Physicochemical Property Effects On Immune Modulating Polymeric Nanoparticles: Potential Applications In Spinal Cord Injury, Daniel J. Kolpek, Jaechang Kim, Hisham Mohammed, John C. Gensel, Jonghyuck Park

Markey Cancer Center Faculty Publications

Nanoparticles (NPs) offer promising potential as therapeutic agents for inflammation-related diseases, owing to their capabilities in drug delivery and immune modulation. In preclinical studies focusing on spinal cord injury (SCI), polymeric NPs have demonstrated the ability to reprogram innate immune cells. This reprogramming results in redirecting immune cells away from the injury site, downregulating pro-inflammatory signaling, and promoting a regenerative environment post-injury. However, to fully understand the mechanisms driving these effects and maximize therapeutic efficacy, it is crucial to assess NP interactions with innate immune cells. This review examines how the physicochemical properties of polymeric NPs influence their modulation of …

Characterizing Locust Anemotaxis: The Impact Of Sensory Perturbations On Flight Behavior, Yi-Xiao Huang

McKelvey School of Engineering Graduate Student Theses & Dissertations

This thesis investigates the effects of sensory perturbations on locust flight behavior, with the goal of better understanding how locusts integrate multiple sensory inputs to maintain flight control. Through a series of experiments, locusts were subjected to visual impairment, turbulent wind conditions, mechanical impairments of their wings and antennae, and pheromonal interference. These perturbations allowed for the exploration of the contributions each sensory pathway makes to flight stability and navigation in a controlled environment.

Results show that while visual impairment does not significantly impact average flight speed, it increases variability in flight stability, suggesting that visual cues are important for …

Type Ii Innate Lymphoid Cell Plasticity Contributes To Impaired Reconstitution After Allogeneic Hematopoietic Stem Cell Transplantation, Sonia J. Laurie, Joseph P. Foster, Danny W. Bruce, Hemamalini Bommiasamy, Oleg V. Kolupaev, Mostafa Yazdimamaghani, Samantha G. Pattenden, Nelson J. Chao, Stefanie Sarantopoulos, Joel S. Parker, Ian J. Davis, Jonathan S. Serody

Chemical and Biochemical Engineering Faculty Research & Creative Works

Type II innate lymphoid cells (ILC2s) maintain homeostasis and barrier integrity in mucosal tissues. In both mice and humans, ILC2s poorly reconstitute after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Determining the mechanisms involved in their impaired reconstitution could improve transplant outcomes. By integrating single-cell chromatin and transcriptomic analyses of transplanted ILC2s, we identify a previously unreported population of converted ILC1-like cells in the mouse small intestine post-transplant. Exposure of ILC2s to proinflammatory cytokines resulted in a mixed ILC1-ILC2 phenotype but was able to convert only a small population of ILC2s to ILC1s, which were found post-transplant. Whereas ILC2s protected against …

Delineating Genetic Influences On Neurodegenerative Disorders And Infectious Diseases Through Advanced Computational Methods, Xiaowei Zhuang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Genetics plays a critical role in understanding the molecular mechanisms underlying neurodegenerative disorders and pathogen evolution in infectious diseases. For example, identifying genetic variants associated with a disease phenotype uncovers functional pathways that could lead to potential drug targets and therapeutic interventions. In addition, tracking the genetic evolution of pathogens enables early detection and warning of infectious disease outbreaks. In both applications, given the large amount of genetic data, advanced computational methods, including longitudinal and multivariate models, could significantly boost the statistical power and capture interrelationships among traits, environmental factors and genetic influences. This dissertation focuses on four applications of …

The Clot Thickens: Investigation Of The Mechanism Behind Hypercoagulation In Covid-19 Patients, Toni Warnick

All Dissertations

Since its emergence in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been associated with cardiovascular complications, which correlate with illness severity and increased mortality. It was initially thought that this hypercoagulable state was induced by endothelial dysfunction or cytokine storm because of SARS-CoV-2 infection. Although platelets have been reported to express the SARS-CoV-2 primary target receptor, angiotensin-converting enzyme 2 (ACE2), this remains controversial due to conflicting findings that suggest minimal to no ACE2 expression on platelets. This ambiguity has led to exploring alternative entry pathways, notably via the virus’s RGD (arginine-glycine-aspartic acid) sequence within its spike protein receptor-binding …

Engineered Microalgae Cultivations Systems: Conversion Of Wastewater Nutrients Into Biofuels And Bioplastics, Jacob Watkins

All Graduate Theses and Dissertations, Fall 2023 to Present

Dissolved Nitrogen and Phosphorus in wastewater can contribute to harmful algae blooms if released into the environment. One technology that can be used to recover dissolved nutrients from wastewater is the Rotating Algae Biofilm Reactor (RABR), which supports microalgae growth in an easily-harvested biofilm and produces nitrogenand phosphorus-rich biomass that can be used to produce slow-release fertilizers, biofuels, and compostable bioplastics. This thesis (1) examines the effects of several environmental factors on the biomass production rate and nutrient removal efficiency of RABRs treating municipal wastewater, (2) quantifies the composition and biofuel yields of microalgae biomass cultivated using a RABR at …